I have 4 rigs running 2 X 295X2 (4 GPU total) and the triple instance crashed the whole box. Needed a hard boot.
> "-k zec zec zec" will use close to 6 GB of vram
> 295X2
> 8Gb card, 4Gb
PER GPUTry "-k zec zec" for 295X2

Yep, tried that. Made swap min 20g and max 40g, ran with -k zec zec and getting
zconn not accepted : null 20
but hash per card is about 35-36 which with one instance was 29-30, but not accepted